I personally have purchased three remotes of the one-button variety for 94-2001 Mercedes C-Class and E-Class vehicles. The owners manual provides instructions on their programming to your vehicle. You will need a correct key blade to put in the remote, do NOT lose the black chip inside will switching blades, if you do it will be worthless
Guess what the dealer told me they wouldn't work as well. Of course they would like to pay $250.00 or more for theirs.
25+ year Mercedes Owner